Background Cardiovascular diseases cause 32% of deaths in Argentina. Aspirin produces a 12% reduction in the incidence of events and is indicated when cardiovascular risk at 10 years is above 10%. The Remediar Program provides aspirin to patients without medical coverage in the public primary care level. Objective To analyze the use of aspirin and estimate its indication. Material and Methods The present study has three designs: 1. Ecological study with cross comparisons of aspirin prescriptions, diagnoses and beneficiaries, by province, of the prescriptions of the Remediar Program. Sources: prescriptions from 6000 health care centers from March 2005 to February 2006. 2. Evaluation of a counterfactual approach. 3. Estimate of medication costs based on results. Results The Remediar Program identified 708 470 beneficiaries >50 years with increased cardiovascular risk. Aspirin was prescribed to 60 408 beneficiaries, with a mean of 2.0 treatments per month/year despite drug availability. The Program provided national coverage for 6.8% of the target population of 882 205 people, with an important variability among provinces. The evaluation of the potential impact of aspirin prescription in three counterfactual scenarios shows that 725 to 21 173 events could have been prevented, and that the cost of the Remediar Program to prevent one event would be of USD 3111 to 6222 during 10 years. Conclusions Underprescription of aspirin, failure to provide a minimum annual number of effective treatments and access issues might limit the impact on health care.